Re: [PATCH 2/2] nvmem: imx: scu: support write

[Srinivas Kandagatla]

On 06/09/2019 07:57, Peng Fan wrote:
> > Subject: [PATCH 2/2] nvmem: imx: scu: support write
>
> Ping..
Thanks for your patience!
I normally do not take patches after rc5 for nvmem.
These will be applied after rc1 is released!

Thanks,
srini
> Thanks,
> Peng.
>
> > From: Peng Fan <peng.fan@xxxxxxx>
> >
> > The fuse programming from non-secure world is blocked, so we could only use
> > Arm Trusted Firmware SIP call to let ATF program fuse.
> >
> > Because there is ECC region that could only be programmed once, so add a
> > heler in_ecc to check the ecc region.
> >
> > Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
> > ---
> >
> > The ATF patch will soon be posted to ATF community.
> >
> >   drivers/nvmem/imx-ocotp-scu.c | 73
> > ++++++++++++++++++++++++++++++++++++++++++-
> >   1 file changed, 72 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/nvmem/imx-ocotp-scu.c b/drivers/nvmem/imx-ocotp-scu.c
> > index 2f339d7432e6..0f064f2e74a8 100644
> > --- a/drivers/nvmem/imx-ocotp-scu.c
> > +++ b/drivers/nvmem/imx-ocotp-scu.c
> > @@ -7,6 +7,7 @@
> >    * Peng Fan <peng.fan@xxxxxxx>
> >    */
> >
> > +#include <linux/arm-smccc.h>
> >   #include <linux/firmware/imx/sci.h>
> >   #include <linux/module.h>
> >   #include <linux/nvmem-provider.h>
> > @@ -14,6 +15,9 @@
> >   #include <linux/platform_device.h>
> >   #include <linux/slab.h>
> >
> > +#define IMX_SIP_OTP			0xC200000A
> > +#define IMX_SIP_OTP_WRITE		0x2
> > +
> >   enum ocotp_devtype {
> >   	IMX8QXP,
> >   };
> > @@ -45,6 +49,8 @@ struct imx_sc_msg_misc_fuse_read {
> >   	u32 word;
> >   } __packed;
> >
> > +static DEFINE_MUTEX(scu_ocotp_mutex);
> > +
> >   static struct ocotp_devtype_data imx8qxp_data = {
> >   	.devtype = IMX8QXP,
> >   	.nregs = 800,
> > @@ -73,6 +79,23 @@ static bool in_hole(void *context, u32 index)
> >   	return false;
> >   }
> >
> > +static bool in_ecc(void *context, u32 index) {
> > +	struct ocotp_priv *priv = context;
> > +	const struct ocotp_devtype_data *data = priv->data;
> > +	int i;
> > +
> > +	for (i = 0; i < data->num_region; i++) {
> > +		if (data->region[i].flag & ECC_REGION) {
> > +			if ((index >= data->region[i].start) &&
> > +			    (index <= data->region[i].end))
> > +				return true;
> > +		}
> > +	}
> > +
> > +	return false;
> > +}
> > +
> >   static int imx_sc_misc_otp_fuse_read(struct imx_sc_ipc *ipc, u32 word,
> >   				     u32 *val)
> >   {
> > @@ -116,6 +139,8 @@ static int imx_scu_ocotp_read(void *context,
> > unsigned int offset,
> >   	if (!p)
> >   		return -ENOMEM;
> >
> > +	mutex_lock(&scu_ocotp_mutex);
> > +
> >   	buf = p;
> >
> >   	for (i = index; i < (index + count); i++) { @@ -126,6 +151,7 @@ static int
> > imx_scu_ocotp_read(void *context, unsigned int offset,
> >
> >   		ret = imx_sc_misc_otp_fuse_read(priv->nvmem_ipc, i, buf);
> >   		if (ret) {
> > +			mutex_unlock(&scu_ocotp_mutex);
> >   			kfree(p);
> >   			return ret;
> >   		}
> > @@ -134,18 +160,63 @@ static int imx_scu_ocotp_read(void *context,
> > unsigned int offset,
> >
> >   	memcpy(val, (u8 *)p + offset % 4, bytes);
> >
> > +	mutex_unlock(&scu_ocotp_mutex);
> > +
> >   	kfree(p);
> >
> >   	return 0;
> >   }
> >
> > +static int imx_scu_ocotp_write(void *context, unsigned int offset,
> > +			       void *val, size_t bytes)
> > +{
> > +	struct ocotp_priv *priv = context;
> > +	struct arm_smccc_res res;
> > +	u32 *buf = val;
> > +	u32 tmp;
> > +	u32 index;
> > +	int ret;
> > +
> > +	/* allow only writing one complete OTP word at a time */
> > +	if ((bytes != 4) || (offset % 4))
> > +		return -EINVAL;
> > +
> > +	index = offset >> 2;
> > +
> > +	if (in_hole(context, index))
> > +		return -EINVAL;
> > +
> > +	if (in_ecc(context, index)) {
> > +		pr_warn("ECC region, only program once\n");
> > +		mutex_lock(&scu_ocotp_mutex);
> > +		ret = imx_sc_misc_otp_fuse_read(priv->nvmem_ipc, index, &tmp);
> > +		mutex_unlock(&scu_ocotp_mutex);
> > +		if (ret)
> > +			return ret;
> > +		if (tmp) {
> > +			pr_warn("ECC region, already has value: %x\n", tmp);
> > +			return -EIO;
> > +		}
> > +	}
> > +
> > +	mutex_lock(&scu_ocotp_mutex);
> > +
> > +	arm_smccc_smc(IMX_SIP_OTP, IMX_SIP_OTP_WRITE, index, *buf,
> > +		      0, 0, 0, 0, &res);
> > +
> > +	mutex_unlock(&scu_ocotp_mutex);
> > +
> > +	return res.a0;
> > +}
> > +
> >   static struct nvmem_config imx_scu_ocotp_nvmem_config = {
> >   	.name = "imx-scu-ocotp",
> > -	.read_only = true,
> > +	.read_only = false,
> >   	.word_size = 4,
> >   	.stride = 1,
> >   	.owner = THIS_MODULE,
> >   	.reg_read = imx_scu_ocotp_read,
> > +	.reg_write = imx_scu_ocotp_write,
> >   };
> >
> >   static const struct of_device_id imx_scu_ocotp_dt_ids[] = {
> > --
> > 2.16.4